No. 447 ] BREEDING HABITS OF CRAYFISH. 1 93 



region there 

 where the yolk material is present. 



All the appendages are present as in the aduh cxcc])! the 

 first and last abdominal appendages so thai the ahdonuMi ter- 

 minates with a very simple broad telson and has no wide tail 

 fan. The eyes are very large. The second antenna- which 

 were packed within the egg shell along the edges ol the carapace 

 external to the legs, I, II, III, Fig. 8, soon alter liatehmg 

 come to be between the legs right and left, iMg. 9. and in 

 this dejected position add to the general helpless and incom- 

 plete appearance of the larva. The rostrum also aids m this 

 infantile expression of the larva as it is very short and blunt 

 and so bent down between the eyes that it cannot be seen 

 except from a ventral view. Both antennae and rostrum 

 appear useless, or at least to be poorly placed or perfected to be 

 of such uses as they seem to have in the adult. 



This larva is so beautifully translucent that the grossly granu- 

 lar blood corpuscles may be seen projected rapidly along the 

 blood spaces in the thorax, abdomen, legs and antennae. These 

 corpuscles have a long tail-like process behind and by this they 

 often remain fixed till dragged loose into the current again. 

 Scattered over the thorax and abdomen but not upon the telson 

 are large, branching pigment cells of a crimson color and some 

 are found also upon the antennules and antenna;, upon the fourth 

 segments of the legs and upon the big claws as indicated m 



The creature remains fixed but moves its 

 movements amongst the gills which may 

 carapace. There are also at times slight j. 

 the abdominal appendages. 



,cen through the 



ns to be carried ( 



large scaphognathite may be seen through the carapace, as 

 indicated in the above figure, bailing water out ot the giu 

 chamber at the rate of perhaps 180 per minute. 1 he^estabhsh- 

 ment of this rhythmic motion so charactenstic of r 



here a slow process 



Before hatching the only rhyt 



the beat of the heart, but after the creature had 



